Question

Jawab beserta jalannya ya kak....

Answer 1

Luas lingkaran 1 = 80 cm^2
phi x r x r = 80 cm^2

a) jika R = 3r, luasnya?
L = phi x R x R
L = phi x 3r x 3r
L = 9 x phi x r x r
L = 9 x 80 cm^2
L = 720 cm^2

b) jika R = 1/4 r, luasnya?
L = phi x R x R
L = phi x 1/4 r x 1/4 r
L = 1/16 x phi x r x r
L = 1/16 x 80 cm^2
L = 5 cm^2